Why are we looking for black grass?
A small amount of grass seed has been spilt along the roadside while being transported between Ashburton and a seed dressing plant in Methven. There is a possibility that the spilt seed contains a very small amount of viable black grass seed – a pest plant that is not found in New Zealand.
Although there is a low chance that black grass will establish from this spill, the Ministry for Primary Industries (MPI) is currently working with Federated Farmers, Foundation for Arable Research and Environment Canterbury Regional Council (ECAN) to develop a surveillance and control strategy in an attempt to mitigate any biosecurity risk to crops in Canterbury and New Zealand.
Why is black grass a pest?
Black grass, also known as slender meadow fox tail, is a serious invasive plant that affects winter crops in Europe, including winter wheat, grass seed, rapeseed, forage legumes and barley. Black grass spreads quickly in cultivated crops, competing for light, nutrients, space and water, resulting in yield loss.
Black grass could have an economic impact on New Zealand agriculture by competing with winter crop production, reducing yields, increasing cultivation costs, affecting purity of seed lines, and impacting on seed markets internationally. In Europe, black grass has developed resistance to many herbicides used for grass weed control. As a result, there are very few options available for controlling it in many crops.
What does black grass look like?
Black grass is an annual that can grow up to a metre high (that is, it can grow above winter crops). The leaves are hairless, with an open sheath, and rolled in the bud. The sheaths can be green or purplish.
The seed heads of black grass are smaller in diameter in proportion to their length than those of other perennial species commonly planted for pasture. The seed heads range from approximately 2.5–12.5 cm tall and 0.3–0.6 cm in diameter.
The seed heads are usually reddish-purple in colour, giving the appearance from a distance of “black grass”. Each black grass seed head contains about 100 seeds that are mainly shed prior to harvest.
When you are most likely to see any sign of black grass Germination will mostly likely take place from September 2013 through to April 2014. Black grass can go from germination to full maturity within 100 days. Therefore, any black grass would be most visible from November 2013 to April 2014. Black grass will begin to set seed around this time, and to prevent further onward spread of the seed, early reporting is vital.
How can you help?
Farmers can assist with surveillance and reduce the chance of black grass becoming established in the area by keeping an eye out for any sign of the pest and, if found, report it immediately.
Black grass (Alopecurus myosuroides) (817 KB)
Page last updated: 19 September 2013